Had this problem for a while and on multiple machines. After it starts printing the mirror images if I try and print out a usage page or a config page it comes out as tight lines on the top of the page and is unreadable. Resetting takes care of the problem for time but it always comes back.
Attempted fixes include
-new formatter boards
-updated firmware
-deleting and reinstalling print drivers
I've checked these boards for solutions and while turning off the mirror print option on the driver might work for that part, what would case the internal reports not to print out correctly?